Apparatus for manufacturing light guide plate

ABSTRACT

The present disclosure relates to the technical field of liquid crystal display. Specifically, it relates to an apparatus for manufacturing light guide plate. The apparatus comprises: a feeding unit having a slit-shaped discharge port, an extrusion unit comprising a conveying roller for conveying the raw material and an extrusion roller for extruding the raw material, and a cutting unit for cutting the light guide plate guided out of the extrusion unit, wherein an elongated recess depressing toward the interior of the extrusion roller is disposed on a roller body of the extrusion roller, in order to manufacture a light guide plate having a varying thickness. The apparatus has the advantages of high production efficiency.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims benefit of Chinese patent application CN201410326527.3, entitled “Apparatus for Manufacturing Light Guide Plate”and filed on Jul. 10, 2014, which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of liquid crystaldisplay. Specifically, it relates to an apparatus for manufacturinglight guide plate.

TECHNICAL BACKGROUND

Large-size side-edge light emitting diode (LED) backlight source tendsto be thinner as it is developed. Therefore, the thickness of a lightguide plate is becoming reduced, for example, from 4 mm, the originalvalue, to 3 mm, further to 2 mm, and even thinner. Due to the decreasedthickness, a reduced cost of the light guide plate, a lighter module,and even a more elegant appearance can be achieved.

However, on the other hand, a thin-type light guide plate can also causesome problems. Typically, the light coupling efficiency of a thin lightguide plate can be reduced due to the limitation of the size of a lightemitting diode (LED).

FIG. 1 schematically shows the light path of a relatively thick lightguide plate in the prior art. The arrows therein indicate thetransmission of light from a light emitting element 1. The lightemitting element 1 is an LED 7030 having a light emitting surface with awidth of 2.6 mm. The thickness of light guide plate 2 in FIG. 1 is 3 mm.

FIG. 2 schematically shows the light path of a relatively thin lightguide plate in the prior art. The arrows therein indicate thetransmission of light from the light emitting element 1. The lightemitting element 1 is an LED 7030 having a light emitting surface with awidth of 2.6 mm. The thickness of light guide plate 2 in FIG. 2 is 2 mm.

Through a comparison of FIG. 2 with FIG. 1, it is easy to understandthat since the light guide plate 2 in FIG. 2 has a decreased thicknesswhich is even lower than the width of the light emitting surface of thelight emitting element 1, part of the light fails to enter the lightguide plate 2.

Therefore, it is easy to understand that the light coupling efficiencybetween the LED 7030 (the light emitting surface of which has a width of2.6 mm) and the light guide plate with a thickness of 2 mm as shown inFIG. 2 is far smaller than that between the LED 7030 and the light guideplate with a thickness of 3 mm as shown in FIG. 1. In this case, loss inlight energy can be incurred.

The idea of using a wedge-shaped light guide plate is thus derived. FIG.3 shows a typical light guide plate having a wedge-shaped projection onthe light incident side thereof. That is, a thickness T₁ of the lightincident side of the light guide plate is larger than a thickness T₂ ofthe rest area thereof. With such a light guide plate, not only the lightcoupling efficiency between a large size light emitting element 10 (LED)and a thin light guide plate 20 can be improved, but also a relativelysmall thickness T₂ of the light guide plate 20 in most area thereof canbe achieved.

A traditional wedge-shaped light guide plate is formed by moldingprocess or injection molding process. The above processes are restrictedin terms of size. Taking injection molding process as an example, atpresent only a light guide plate of 32 inches at best can be obtaineddue to the limitation of the machine tonnage. No forming process orrelated equipment exists yet in the prior art for producing awedge-shaped light guide plate of larger size.

SUMMARY OF THE INVENTION

In order to solve the problem in the prior art of being unable tomanufacture a wedge-shaped light guide plate of required size(relatively large), the present disclosure provides an apparatus formanufacturing light guide plate having a wedge-shaped projection on thelight incident side thereof (the typical structure thereof is as shownin FIG. 3). In the meantime, as compared with the prior art, a lightguide plate of larger size can be manufactured by the apparatusaccording to the present disclosure without being limited by the designof the apparatus itself.

The present disclosure provides an apparatus for manufacturing lightguide plate. According to embodiment 1, the apparatus comprises afeeding unit having a slit-shaped discharge port for supplying rawmaterial of the light guide plate, an extrusion unit comprising aconveying roller for conveying the raw material and an extrusion rollerfor extruding the raw material, and a cutting unit for cutting the lightguide plate guided out of the extrusion unit, wherein an elongatedrecess depressing toward the interior of the extrusion roller isdisposed on a roller body of the extrusion roller, in order tomanufacture a light guide plate having a varying thickness.

According to embodiment 2 which is obtained through improvements on thebasis of embodiment 1, the conveying roller is located at one side ofthe raw material and the extrusion roller is located at the other sidethereof, and the conveying roller is disposed at a positioncorresponding to the extrusion roller for cooperation therewith. Theextrusion roller and a corresponding conveying roller form pairedrollers for extruding the raw material together, and the rest conveyingrollers are mainly used to convey the raw material.

According to embodiment 3 which is obtained through improvements on thebasis of embodiment 2, the apparatus comprises only one extrusionroller, and in the extrusion unit, the rotating direction of the rollerbody of the extrusion roller and that of the roller body of theconveying roller are consistent with the advancing direction of the rawmaterial. By means of which, the instantaneous rolling contact portionsin the whole system all move toward the same direction.

According to embodiment 4 which is obtained through improvements on thebasis of embodiment 2, the recess surrounds the roller body of theextrusion roller along the entire circumference thereof, and theextension direction of the recess is perpendicular to a central rotatingaxle of the extrusion roller. The wedge-shaped projection of a lightguide plate thus obtained extends along the advancing direction (i.e.the rotating direction of the roller body) of the light guide plate.

According to embodiment 5 which is obtained through improvements on thebasis of embodiment 4, the recess is located at an axial end of theroller body.

According to embodiment 6 which is obtained through improvements on thebasis of embodiment 4, the recess is located at an axial center of theroller body.

Certainly, the number and position of recess can be adjusted accordingto the relationships between the axial length of the roller body and thesize of the target light guide plate.

According to embodiment 7 which is obtained through improvements on thebasis of embodiment 2, the recess extends axially from one end of theroller body of the extrusion roller to the other end thereof, theextension direction of the recess being parallel to the central rotatingaxle of the extrusion roller. The wedge-shaped projection of a lightguide plate thus obtained extends along a direction perpendicular to theadvancing direction of the light guide plate, i.e. along an axialdirection of the roller body.

According to embodiment 8 which is obtained through improvements on thebasis of embodiment 7, a plurality of recesses are distributed on thecircumference of the roller body of an extrusion roller at regularintervals.

According to embodiment 9 which is obtained through improvements on thebasis of embodiment 8, two recesses are arranged on an extrusion roller.

According to embodiment 10 which is obtained through improvements on thebasis of embodiment 7, only one recess is arranged on an extrusionroller.

Certainly, the number and position of recess can be adjusted accordingto the relationships between the perimeter of the roller body and thesize of the target light guide plate.

According to embodiment 11 which is obtained through improvements on thebasis of any one of embodiments 7 to 10, the cross section of the recessis in the shape of a sector, the side walls of which form the sides ofthe sector and an opening thereof forms a long arc of the sector. Aprojection (relatively thick area) on the light guide plate extruded bysuch a recess is wedge shaped.

According to embodiment 12 which is obtained through improvements on thebasis of any one of embodiments 7 to 10, the guide light plate guidedout of the extrusion unit comprises a relatively thin area and arelatively thick area and the cutting unit cuts the light guide plate onthe relatively thick area. In this case, a large light guide plate ofspecified size having a wedge-shaped projection (relatively thick area)on the light incident side thereof can be obtained. After subsequentforming and polishing steps, the light guide plate can be applied to adisplay device.

A light guide plate having a wedge-shaped projection on the lightincident side thereof can be manufactured through the apparatusaccording to the present disclosure. Such a light guide plate can be cutinto any size as required, especially a size larger than that can beobtained in the prior art. On the other hand, the whole manufacturingprocess can be implemented in the apparatus. Therefore, the advantagesof smooth operation, high production efficiency, easy maintenance, andlow integration cost can be realized.

The above technical features can be combined in any manner orsubstituted with equivalent technical features, as long as the objectiveof the present disclosure is met.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present disclosure will be described in details based on thefollowing embodiments with reference to the accompanying drawings. Inwhich:

FIG. 1 schematically shows the light path of a relatively thick lightguide plate in the prior art;

FIG. 2 schematically shows the light path of a relatively thin lightguide plate in the prior art;

FIG. 3 schematically shows the structure of a light guide plate to bemanufactured by an apparatus according to the present disclosure;

FIG. 4 schematically shows the structure of an apparatus for makinglight guide plate according to Example 1 of the present disclosure;

FIG. 5 shows a side view of the apparatus for making light guide plateaccording to Example 1 of the present disclosure;

FIG. 6 shows an extrusion roller of the apparatus for making light guideplate according to Example 1 of the present disclosure;

FIG. 7 shows a finished light guide plate manufactured by the apparatusfor making light guide plate according to Example 1 of the presentdisclosure;

FIG. 8 shows a side view of the light guide plate of FIG. 7;

FIG. 9 shows an extrusion roller of the apparatus for manufacturinglight guide plate according to Example 2 of the present disclosure;

FIG. 10 shows a finished light guide plate manufactured by the apparatusfor making light guide plate according to Example 2 of the presentdisclosure;

FIG. 11 shows a side view of an apparatus for making light guide plateaccording to Example 3 of the present disclosure;

FIG. 12 shows a perspective view of a roller body of an extrusion rollerof the apparatus for making light guide plate according to Example 3 ofthe present disclosure;

FIG. 13 shows a side view of the roller body of the extrusion roller inFIG. 12 observed along an axial direction thereof;

FIG. 14 shows the size relationship between the roller body of theextrusion roller in FIG. 13 and the light guide plate obtained;

FIG. 15 shows an alternative structure of the apparatus for making lightguide plate according to Example 3 of the present disclosure; and

FIG. 16 shows an extrusion roller of an apparatus for making light guideplate according to Example 4 of the present disclosure.

In the drawings, the same components are indicated with the same sign.The drawings are not drawn to actual scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be further described with reference to theaccompanying drawings.

As described above, FIG. 3 shows a light guide plate 20 having awedge-shaped projection on the light incident side thereof. The lightguide plate 20 is the light guide plate to be manufactured by anapparatus according to the present disclosure. Generally speaking, theobjective of the present disclosure is to manufacture a light guideplate having a varying thickness. The specific form of the light guideplate is not limited to that as shown in FIG. 3. For example, thewedge-shaped projection can be arranged on another position of the lightguide plate, or the projection can have a cross section of a differentshape, such as rectangle or arc.

As clearly shown in FIG. 3, a thickness T₁ of a light incident side ofthe light guide plate 20 is larger than a thickness T₂ of the rest areathereof. With such a light guide plate, not only the light couplingefficiency between a large size light emitting element 10 (LED) and athin light guide plate 20 can be improved, but also a relatively smallthickness T₂ of the light guide plate 20 on most area thereof can beguaranteed.

The manufacturing process of a large size flat light guide platecomprises the following steps. First, molten macromolecule material(typically, polymethyl methacrylate (PMMA) or styrene-methylmethacrylate copolymer (MS)) is extruded through several extrusionrollers. Second, the extruded material is cooled. A large light guideplate is thus obtained. The apparatus according to the presentdisclosure is developed and improved based on the above technicalprinciple.

FIG. 4 schematically shows an apparatus 50 for manufacturing light guideplate according to Example 1 of the present disclosure.

As shown in FIG. 4, the apparatus 50 in Example 1 comprises a feedingunit 100. The feeding unit 100 can be a container having a slit-shapeddischarge port for supplying raw material 101 of the light guide plate.After the raw material 101 flows out of the feeding unit 100, it forms aroughly plate shaped body due to the limitation of the slit-shapeddischarge port. The plate shape of the raw material 101 at this momentis merely for the convenience of the following steps, and is a littledeviated from the final form of the light guide plate.

The apparatus 50 further comprises an extrusion unit. The extrusion unitcomprises a conveying roller for conveying the raw material 101, and anextrusion roller for extruding the raw material 101. According toExample 1 as shown in FIG. 4, the apparatus 50 comprises conveyingrollers 201, 203, and 204, as well as extrusion roller 202. For an easyoperation, the conveying rollers 201, 203, and 204 are arranged on oneside of the raw material 101, and the extrusion roller 202 alone isarranged on the other side thereof. The conveying roller 201 is disposedat a position corresponding to the extrusion roller 202 for cooperationtherewith. The extrusion roller 202 and the conveying roller 201 formpaired rollers for extruding the raw material 101 together (detaileddescription will be provided later). Then, the extrusion roller 202further forms paired rollers with the conveying roller 203. The mainfunction of the conveying roller 204 is to convey the raw material 101.

FIG. 5 shows a side view of the apparatus in FIG. 4. The arrows thereinindicate the rotating directions of the conveying rollers 201, 203, and204 and that of the extrusion roller 202. As shown in FIG. 5, therotating directions of all of the extrusion roller and conveying rollersin the extrusion unit (consisting of conveying rollers 201, 203, and 204and extrusion roller 202 in Example 1) are consistent with the advancingdirection of the raw material 101. As shown in FIG. 5, the raw material101 advances from left to right. The conveying rollers 201, 203, and 204on one side of the raw material 101 rotate clockwisely and the extrusionroller 202 on the other side thereof rotates counter-clockwisely, suchthat the instantaneous rolling contact portions in the whole system allmove toward the same direction.

As shown in FIG. 5, the apparatus 50 further comprises a cutting unit230 for cutting a light guide plate 300 guided out of the extrusionunit. It is understandable that after the extrusion, the raw material101 has become a light guide plate 300 having a shape as required,which, however, is larger than needed at this stage. Thus it isnecessary to use the cutting unit 230 to cut the light guide plate 300into a size that matches a display device of specific model.

FIG. 6 shows an extrusion roller 210 (corresponding to the extrusionroller 202 as shown in FIGS. 4 and 5) of the apparatus according toExample 1 of the present disclosure. According to FIG. 6, an elongatedrecess 213 depressing toward the interior of the extrusion roller 210 isdisposed on a roller body 212 of the extrusion roller 210. The rawmaterial 101 is extruded by the extrusion roller 210, and thus formed alight guide plate having a varying thickness (such as the light guideplate 20 as shown in FIG. 3). Referring to FIG. 6, the recess 213entirely surrounds the roller body 212 of the extrusion roller 210 alongthe circumferential direction thereof, and an extension direction of therecess 213 is perpendicular to a central rotating axle 211 of theextrusion roller 210. In other words, the recess 213 extends around theentire circumference of the roller body 212.

It can be clearly seen from FIG. 6 that the elongated recess 213 islocated at an axial end of the roller body 212. According to specificmanufacturing requirements of size and model, recess or recesses 213 canbe arranged at an axial end of the roller body 212 or at both axial endsthereof. The radial dimension of the roller body 212 at the recess 213is apparently smaller than that of the roller body 212 on the rest areathereof. That is, a diameter D₂ of the roller body 212 at the recess 213on the axial end is smaller than a diameter D₁ of the roller body 212 onthe rest area. The recess 213 further comprises an inclined side wall214 having an axial width L. The side wall 214 is delimited by the dashlines in FIG. 6.

FIG. 7 shows a finished light guide plate 300 manufactured by theapparatus for manufacturing light guide plate according to Example 1 ofthe present disclosure. As shown in FIG. 7, the light guide plate 300comprises a relatively thin area 301, a relatively thick area 302, and aslope area 303 having certain inclination between the relatively thinarea 301 and the relatively thick area 302. The hatched arrow A in FIG.7 indicates the rotating direction of a roller body of an extrusionroller exerting upon the light guide plate 300.

FIG. 8 shows a side view of the light guide plate in FIG. 7. The slopearea 303 is delimited by two dash lines in FIG. 8. It is easy tounderstand that the corresponding surfaces between the roller body 212of the extrusion roller 210 and the light guide plate 300 engage witheach other in a concave-convex manner. Referring to FIGS. 6 and 8, thewider portion (the non-recessed area) of the roller body 212 correspondsto the relatively thin area 301 of the light guide plate 300. The recess213 on the roller body 212 corresponds to the relatively thick area 302of the light guide plate 300. The side wall 214 of the roller body 212corresponds to the slope area 303 of the light guide plate 300.

Furthermore, the size of the roller body 212 is also correlative to thatof the wedge-shaped light guide plate 300, as shown by the equationD₁−D₂=2(T₁−T₂), wherein D₁ is the diameter of the wider portion of theroller body 212, D₂ is the diameter of the roller body 212 at the recess213, T₁ is the thickness of the relatively thick area of the light guideplate 300, and T₂ is the thickness of the relatively thin area of thelight guide plate 300. Of course, the above equation of the sizerelationship reflects merely a theoretical value. It is easy for aperson skilled in the art to understand that certain tolerance of theproduct size is inevitable in actual manufacturing process. On anotheraspect, an axial width L of the side wall 214 of the recess 213 ofroller body 212 equals to an axial width W of the slope area 303 of thelight guide plate 300.

Referring to FIG. 5 again, in Example 1, the wedge-shaped projection(the relatively thick area 302) of the light guide plate 300 extendsalong the advancing direction of the raw material 101 of the light guideplate. After the roll forming process, the light guide plate 300obtained can be cut along its edge in a machine direction (MD) andpolished through a forming machine stand, thereby further forming awedge-shaped projection on a light incident side of the finished lightguide plate 300.

FIG. 9 shows an extrusion roller 410 of an apparatus for manufacturinglight guide plate according to Example 2 of the present disclosure. Thestructure of the apparatus in Example 2 is substantially the same withthat of the apparatus in Example 1 as shown in FIGS. 4 and 5, and thuswill not be described in details herein. The main difference of Example2 from Example 1 is that in Example 2, the extrusion roller 210 as shownin FIG. 6 is replaced with the extrusion roller 410 as shown in FIG. 9,which factions as the extrusion roller 202 in FIGS. 4 and 5.

As shown in FIG. 9, elongated recesses 413 and 415 depressing toward theinterior of the extrusion roller 410 are disposed on a roller body 412of the extrusion roller 410. The recess 413 is disposed at an axial endof the roller body 412, and the recess 415 is disposed at an axialcenter of the roller body 412.

By extruding the raw material 101 through the extrusion roller 410, alight guide plate having a varying thickness (such as the light guideplate 20 as shown in FIG. 3) can be manufactured. Referring to FIG. 9,the recesses 413 and 415 surround the roller body 412 of the extrusionroller 410 along the entire circumference thereof, and the extensionsthereof are perpendicular to a central rotating axle 411 of theextrusion roller 410. In other words, each of the recesses 413 and 415extend along the circumference of the roller body 412 for 360 degrees.

The diameter of the roller body 412 at each of the recesses 413 and 415is apparently smaller than that of the rest area of the roller body 412,i.e. a diameter D₂ of the recess 415 at the axial center of the rollerbody 412 is smaller than a diameter D₁ at the non-recessed area of theroller body 412.

FIG. 10 shows a finished light guide plate 500 manufactured by theapparatus for manufacturing light guide plate according to Example 2 ofthe present disclosure. It is easy to understand that the correspondingsurfaces between the roller body 412 of the extrusion roller 410 and thelight guide plate 500 engage with each other in a concave-convex manner.Referring to FIGS. 9 and 10, the wider portion (the non-recessed area)of the roller body 412 corresponds to a relatively thin area 501 of thelight guide plate 500. The recess 413 at the axial end of the rollerbody 412 corresponds to a relatively thick area 502 of the edge of thelight guide plate 500. The recess 415 at the axial center of the rollerbody 412 corresponds to a relatively thick area 505 at the center of thelight guide plate 500.

When the axial length of the extrusion roller 412 is larger than twicethe required length of a light guide plate, Example 2 can be adopted.That is, an elongated recess 415 which extends perpendicular to thecentral rotating axle 411 of the extrusion roller 410 can be disposed atthe axial center of the roller body 412, and surrounds the entirecircumference of the roller body 412.

Of course, the number and position of recess in Example 1 and Example 2are only exemplary but not restrictive. Based on the axial length of theroller body and the required size of the light guide plate, the numberand position of elongated recess on the roller body of the extrusionroller can be adjusted accordingly. A plurality of elongated recesseswhich are perpendicular to the central rotating axle of the roller bodyand surround the circumference thereof can also be arranged on theroller body at regular intervals. Specifically, the elongated recess canbe a slot having a trapezoidal cross section.

FIG. 11 shows a side view of an apparatus for manufacturing light guideplate according to Example 3 of the present disclosure. As shown in FIG.11, an apparatus 60 in Example 3 comprises a feeding unit 100. Further,the apparatus 60 comprises an extrusion unit, comprising conveyingrollers for conveying raw material 101 of the light guide plate and anextrusion roller for extruding the raw material 101. In Example 3 asshown in FIG. 11, the apparatus 60 comprises conveying rollers 601, 603,and 604, as well as an extrusion roller 602. For an easy operation, theconveying rollers 601, 603, and 604 are arranged on one side of the rawmaterial 101, and the extrusion roller 602 alone is arranged on theother side thereof. The conveying roller 601 is arranged on a positioncorresponding to the extrusion roller 602 for cooperation therewith. Theextrusion roller 602 and the conveying roller 601 form paired rollersfor extruding the raw material 101 together (detailed description willbe provided later). And then the extrusion roller 602 pairs with theconveying roller 603. The conveying roller 604 is mainly used to conveythe raw material 101.

FIG. 11 further indicates the rotating directions of the conveyingrollers 601, 603, and 604 and that of the extrusion roller 602 witharrows. As shown in FIG. 11, the rotating directions of all of theextrusion roller and conveying rollers in the extrusion unit (consistingof conveying rollers 601, 603, and 604 and an extrusion roller 602 inExample 3) are consistent with the advancing direction of the rawmaterial 101. In FIG. 11, the raw material 101 advances from left toright. The conveying rollers 601, 603, and 604 on one side of the rawmaterial 101 rotate clockwisely, and the extrusion roller 602 on theother side thereof rotates counter-clockwisely, such that theinstantaneous rolling contact portions in the whole system all movetoward the same direction.

As shown in FIG. 11, the apparatus 60 further comprises a cutting unit630 for cutting the light guide plate 600 guided out of the extrusionunit. It is easy to understand that after the extrusion process throughthe extrusion unit, the raw material 101 has become a light guide plate600 having a shape as required, which, however, is larger than needed atthis stage. Thus it is necessary to use the cutting unit 630 cuts thelight guide plate 600 into a size that matches a display device ofspecific model.

FIG. 12 shows a perspective view of a roller body of an extrusion rollerof the apparatus for manufacturing light guide plate according toExample 3 of the present disclosure. In Example 3, the extrusion roller602 of the apparatus 60 as shown in FIG. 11 is replaced with theextrusion roller 610 as shown in FIG. 12.

As shown in FIG. 12, an elongated recess 612 is arranged on a rollerbody 611 of the extrusion roller 610. The recess 612 extends along anaxial direction of the roller body 611 from an axial end of the rollerbody 611 to the other axial end thereof. An extension direction of theelongated recess 612 is parallel to a central rotating axle of theextrusion roller 610. Although the central rotating axle is not shown inFIG. 12, it is easy for a person skilled in the art to understand thatthe central rotating axle is usually located at the central axle of theroller body.

FIG. 13 shows a side view of the roller body 611 of the extrusion roller610 as shown in FIG. 12 observed from an axial direction thereof. Asshown in FIG. 13, the elongated recess 612 depressing toward theinterior (i.e. depressing toward a central rotating axle 613) of theextrusion roller 610 is arranged on the roller body 611. Preferably, thecross section of the recess 612 is in the shape of a sector, the sidewalls of which form the sides of the sector and the opening side formsthe long arc of the sector. In this case, a projection (relatively thickarea) on the light guide plate obtained under the extrusion of therecess 612 is wedge shaped.

FIG. 14 shows the size relationship between the roller body 611 of theextrusion roller 610 in FIG. 13 and a light guide plate obtained,wherein the upper part of FIG. 14 shows a side view of the roller body611 of the extrusion roller 610 observed from an axial directionthereof, and the lower part of FIG. 14 shows a side view of a lightguide plate obtained by the extrusion of the extrusion roller 610.

A radius R₂ at the recess of the roller body of the extrusion roller asshown in FIG. 14 is smaller than a radius R₁ of the roller body at therest area (the non-recessed area). On another aspect, the correspondingsurfaces between the roller body of the extrusion roller and the lightguide plate engage with each other in a concave-convex manner. The restarea of the roller body (the non-recessed area) corresponds to arelatively thin area of the light guide plate, and the recess on theroller body corresponds to a relatively thick area of the light guideplate. Thus, a thickness T₁ of the relatively thick area of the lightguide plate is larger than a thickness T₂ of the relatively thin area ofthe light guide plate.

The size of the roller body is also correlative to that of thewedge-shaped light guide plate, as shown in the equation R₁−R₂=T₁−T₂,wherein R₂ is the radius of the roller body at the recess, R₁ is theradius of the roller body on the rest area (the non-recessed area), T₁is the thickness of the relatively thick area of the light guide plate,and T₂ is the thickness of the relatively thin area of the light guideplate. Of course, the above equation of the size relationship merelyreflects a theoretical value. It is easy for a person skilled in the artto understand that certain tolerance of the product size is inevitablein actual manufacturing process. As shown in the drawings, an inclinedside wall is further provided between the recess and the non-recessedarea of the roller body, thus a slope area having a certain inclinationalso exists between the relatively thin area and the relatively thickarea of the light guide plate. It is easy to understand that thedimension of the side wall along a circumferential direction equals tothat of the slope area along a corresponding circumferential direction.

Referring to FIG. 11 again, when a large light guide plate 600 iscooled, it is cut by the cutting unit 630 along a wedge-shapedprojection 705 (the relatively thick area), so as to obtain a lightguide plate of specified size having a wedge-shaped projection (therelatively thick area) at a light incident side thereof. After thefollowing forming and polishing steps, the light guide plate can besubsequently applied to a display device.

FIG. 15 shows an alternative structure for the apparatus in Example 3 ofthe present disclosure. An apparatus 80 as shown in FIG. 15 issubstantially the same as the apparatus 60 as shown in FIG. 11, and thuswill not be described in details. The main differences of the apparatus80 from the apparatus 60 are the number and positions of the conveyingrollers. As shown in FIG. 15, the apparatus 80 comprises four conveyingrollers 801, 803, 804, and 805, as well as an extrusion roller 806having a groove 714. The conveying rollers and the extrusion roller areno longer at the same level. The conveying roller 801 and the extrusionroller 806 are located at a higher level, and form paired rollers forextruding raw material 101 of the light guide plate together. Then, theextrusion roller 806 pairs with the conveying roller 803. The conveyingrollers 804 and 805 are mainly used to convey the raw material. Acutting unit 730 is used to cut the light guide plate.

FIG. 16 shows an extrusion roller of an apparatus for manufacturinglight guide plate according to Example 4 of the present disclosure. Thestructure of the apparatus in Example 4 is substantially the same asthat of the apparatus in Example 3 as shown in FIG. 11, and thus willnot be described in details. The main difference of Example 4 fromExample 3 is that the extrusion roller 610 as shown in FIG. 12 isreplaced with an extrusion roller 910 as shown in FIG. 16, whichfunctions as the extrusion roller 602 as shown in FIG. 11.

The extrusion roller 910 comprises a central rotating axle 914 and aroller body 911. Two elongated recesses 913 are arranged on the rollerbody 911. The recesses 913 extend along an axial direction of the rollerbody 911 from one axial end to the other thereof.

As a variation of Example 4, the roller body of the extrusion roller cancomprise a plurality of elongated recesses, which extend along an axialdirection of the roller body and are distributed on the circumferencethereof at regular intervals.

The number of recess on the roller body can be determined according tothe perimeter of the roller body and the corresponding size of the lightguide plate.

(1) Take a 55-inch light guide plate with its short side being the lightincident side as an example, the long side has a length of 1240 mm.Accordingly, the diameter of a roller body is 400 mm (the perimeterthereof is about 1260 mm). In this case, only one elongated recess alongan axial direction of the roller body is needed for obtaining a lightguide plate having a wedge-shaped projection on the short light incidentside thereof.

(2) Take a 32-inch light guide plate with its short side being the lightincident side as an example, the diameter of a roller body is 500 mm(the perimeter thereof is about 1570 mm). When a light guide platehaving a wedge-shaped projection is manufactured, two elongated recessesspaced apart for 180 degrees relative to each other can be disposed onthe roller body along an axial direction thereof, so that two lightguide plates each having a wedge-shaped projection formed on thecorresponding short light incident side can be manufactured by rotatingthe roller body for one round.

If necessary, the elongated recesses in Example 1 and Example 2 andthose in Example 3 and Example 4 can be combined together, so as toobtain a required light guide plate having projections on the surfacethereof.

While the present disclosure have been described with reference topreferred embodiments, various modifications can be made to the presentdisclosure without departing from the scope and spirit of the presentdisclosure and components in the present disclosure could be substitutedwith equivalents. In particular, as long as there is no structuralconflict, all the technical features mentioned in all the embodimentsmay be combined together in any manner. The present disclosure is notlimited to the specific embodiments disclosed in the description, butrather includes all the technical solutions falling into the scope ofthe claims.

1. An apparatus for manufacturing light guide plate, comprising: afeeding unit having a slit-shaped discharge port for supplying rawmaterial of the light guide plate, an extrusion unit comprising aconveying roller for conveying the raw material and an extrusion rollerfor extruding the raw material, and a cutting unit for cutting the lightguide plate guided out of the extrusion unit, wherein an elongatedrecess depressing toward the interior of the extrusion roller isdisposed on a roller body of the extrusion roller, in order tomanufacture a light guide plate having a varying thickness.
 2. Theapparatus according to claim 1, wherein the conveying roller is locatedat one side of the raw material and the extrusion roller is located atthe other side thereof, and the conveying roller is disposed at aposition corresponding to the extrusion roller for cooperationtherewith.
 3. The apparatus according to claim 2, wherein the apparatuscomprises only one extrusion roller, and in the extrusion unit, therotating direction of the roller body of the extrusion roll and that ofthe roller body of the conveying roller are consistent with theadvancing direction of the raw material.
 4. The apparatus according toclaim 2, wherein the recess surrounds the roller body of the extrusionroller along the entire circumference thereof, and the extensiondirection of the recess is perpendicular to a central rotating axle ofthe extrusion roller.
 5. The apparatus according to claim 4, wherein therecess is located at an axial end of the roller body.
 6. The apparatusaccording to claim 4, wherein the recess is located at an axial centerof the roller body.
 7. The apparatus according to claim 2, wherein therecess extends axially from one end of the roller body of the extrusionroller to the other end thereof, the extension direction of the recessbeing parallel to a central rotating axle of the extrusion roller. 8.The apparatus according to claim 7, wherein a plurality of recesses aredistributed on the circumference of the roller body of the extrusionroller at regular intervals.
 9. The apparatus according to claim 7,wherein the cross section of the recess is in the shape of a sector, theside walls of which form the sides of the sector and an opening thereofforms a long arc of the sector.
 10. The apparatus according to claim 8,wherein the cross section of the recess is in the shape of a sector, theside walls of which form the sides of the sector and the opening thereofforms the long arc of the sector.
 11. The apparatus according to claim7, wherein the guide light plate guided out of the extrusion unitcomprises a relatively thin area and a relatively thick area, and thecutting unit cuts the light guide plate on the relatively thick area.12. The apparatus according to claim 8, wherein the guide light plateguided out of the extrusion unit comprises a relatively thin area and arelatively thick area, and the cutting unit cuts the light guide plateon the relatively thick area.